Hoping to reverse its financial slump and reassure investors, Yahoo Inc. unveiled a management overhaul Thursday that aims to improve its Internet products and advertising business.

The changes, expected for more than a week, create three new groups under Yahoo President Sue Decker, who modestly increases her authority under the new structure.

But the question remained whether the reshuffling is too little too late, as the Sunnyvale Web portal tries to fight for control of its board and revive its business following an aborted takeover bid by Microsoft Corp.

Under the plan, Ash Patel, a Yahoo veteran who oversees a big chunk of underlying software, will lead a group that manages and creates the company's broad portfolio of products such as search, e-mail and instant messaging.

Hilary Schneider, an executive in charge of the company's advertising who is close to Decker, will now oversee most of the U.S. business.

A third team that mines the vast amounts of data Yahoo collects about it users' habits will be led by an executive to be named later.

Jerry Yang, Yahoo's chief executive, said the shift is "designed to put us in an even better position to leverage our leading global audience and capture the opportunity we see in the convergence of search and display advertising."

Over the past year and a half, Yahoo has undergone several restructurings that included job cuts, the elimination of products deemed no longer central to its business, and the departure of top executives including former CEO Terry Semel. Those overhauls' failure to revive the company signals that this latest attempt is no sure thing.

Kevin Landis, chief investment officer for Firsthand Funds, a mutual fund company in San Jose that owned 136,000 Yahoo shares as of the end of March, said Yahoo's management had to shake things up, given the company's predicament. But he added that rarely does a successful corporate turnaround hinge on a management reorganization.

"They needed to do something," Landis said.

The restructuring comes a little over a month before a high-profile showdown with billionaire investor Carl Icahn, who has launched a battle to replace the company's board with his own slate of directors. Anything Yahoo can point to as an antidote to its malaise may help bolster its case that its current board should be re-elected.

Many investors are angry that Yahoo's board failed to accept Microsoft's $47.5 billion takeover bid, which would have paid $33 per share for the company. But since the two technology giants called off talks June 12, Yahoo's shares have sunk sharply, leaving Yang's future in doubt.

On Thursday, Yahoo's stock fell 64 cents, or 3 percent, to $21.37, indicating investor skepticism about the new organization chart.

Since the Microsoft talks collapsed, and the planned reorganization took shape, several top Yahoo executives have resigned or plan to do so soon, including Jeff Weiner, executive vice president who oversaw most consumer-facing products; Vish Makhijani, who led the search team; Qi Lu, executive vice president of search and advertising technology; Brad Garlinghouse, a senior vice president in charge of communications products; and the founders of the Flickr photo sharing service, Caterina Fake and Stewart Butterfield. A handful of other executives in Yahoo's technology group, whose management also was overhauled Thursday, lost their jobs, according to a person familiar with the matter.